Modeling of laminated veneer lumber - A study of the material properties for thick structural elements
Typ
Examensarbete för masterexamen
Program
Applied mechanics (MPAME), MSc
Publicerad
2020
Författare
Ek, John
Norbäck, Viktor
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This thesis studies the material properties of laminated veneer lumber (LVL). LVL is a timber product
made of thin veneers of wood, glued together to form a laminate. The work has been carried out with
the aim of providing a better understanding of LVL when designing large structures, in particular the
thesis is related to the large scale application of wind turbine towers.
The project consists of two major parts, initially a study of the possibility to use laminate theory
for evaluation of LVL stiffness parameters. From this study it was found that the laminate theory used,
in combination with the accessible material parameters provide an unfit description of the material.
Consequently the second part of the project investigates the material behaviour using a more advanced
three dimensional model, taking the effect of variability in veneer properties and the influence of knots,
modeled as stiffness free voids, into account. The study reveal that increasing the number of veneers,
increases the effect from the variability of veneers and reduces the influence of knots.
Conclusions from the model suggests there are both beneficial and unfavourable effects when designing
thick LVL structures. In order to account for these effects which currently is not practice, a more elaborate
three dimensional model need to be studied, analyzing the material further.
Beskrivning
Ämne/nyckelord
Laminated veneer lumber (LVL), , Laminate theory, , Finite elements